The pots were found during excavations at Cladh HallanImage: Mike Parker Pearson Sheffield University

By BBC News Online's Helen Briggs

Archaeologists have found cow's milk in cooking pots at an Iron Age settlement in the Western Isles of Scotland.

The discovery suggests that the inhabitants in the Outer Hebrides could have been farming animals for milk as long as 2,500 years ago.

Lead researcher Oliver Craig told BBC News Online: "It is possible that early Iron Age 'Scots' had milk with their porridge.

"At the time, they were using cereals like barley but not oats so they could have had a type of porridge similar to that which is popular in Sweden today."

Indeed, the peoples living in that part of Scotland at the time may well have been invaders from Scandinavia.

Milk proteins

The traces of cow's milk were detected in fragments of 2,500-year-old cooking pots at Cladh Hallan, South Uist.

Shards of the vessels were uncovered during excavations of an early Iron Age roundhouse on the island, along with animal bones and flint tools.

Tests using artificial antibodies raised against a component of cow's milk confirmed the presence of milk proteins in seven out of nine of the vessels.

The finding indicates that farming by early inhabitants of the Western Isles was surprisingly well developed.

Dr Oliver Craig, of Newcastle University, who carried out the analysis said: "The interesting thing about this site in Scotland is its location and the harsh environment around it.

"People had not expected them to be sophisticated farmers and this evidence would tend to contradict that."

Writing in the scientific journal Nature, the team said the new evidence resolved an age-old debate about whether early inhabitants of the islands subsisted on dairy or meat farming.

Iron Age diets

In the archaeological record, dairy farming is regarded as more advanced than beef farming because it is a higher-risk, more intensive procedure.

Bones of calves were also found at the site, suggesting that the Iron Age farmers were slaughtering the young animals to maintain milk production.

The scientists are now testing the cooking pots for signs of other animal and plant products, such as meat and waxes.

This should provide a more accurate picture of the Iron Age diets of these early inhabitants.

Dr Mike Parker Pearson, of Sheffield University's Department of Archaeology, who collaborated on the project, said: "We've got a whole new doorway open to us in terms of the evidence because we can start to look at the foods they were eating and preparing in these parts."